Two small earthquakes shake Berks County towns

This map provided by the United States Geological Society shows the epicenter of the second of two small earthquakes in Berks County early Wednesday morning. The second quake was reported just before 6 a.m. in Flying HIlls, Cumru Township, and was a magnitude 1.7.

This map provided by the United States Geological Society shows the epicenter of the second of two small earthquakes in Berks County early Wednesday morning. The second quake was reported just before 6 a.m. in Flying HIlls, Cumru Township, and was a magnitude 1.7.

A pair of earthquakes early Wednesday morning in Berks County shook two towns just outside of Reading.

According to the United States Geological Society, the first quake, a magnitude 1.9, was recorded shortly before 3 a.m. Wednesday near Shillington Borough. The second quake, a magnitude 1.7, was reported just before 6 a.m. about 4½ miles away in Flying Hills in Cumru Township.

Shillington Borough Manager Micheal Mountz said he didn’t even know the area had experienced an earthquake until he saw the morning news.

No damage was reported, he said.

Earthquakes are not uncommon in the area, thanks to the Lancaster Seismic Zone.

“In that sense, our little pocket here has some of the highest risk for earthquakes in Pennsylvania,” said Sam Earman, an associate professor of geology at Millersville University.

People are certainly going to notice. You can hear some rumbling, or booms can be heard.— Millersville University professor Sam Earman on earthquakes that register 2.0 or less

The zone encompasses Lancaster, Berks and York counties and extends into a small portion of Lehigh County, Earman said.

Earthquakes are associated with fault lines under the earth’s surface. Faults are fractures in the earth’s crust where rocks on either side of the crack have slipped past each other.

“Pennsylvania has hundreds and hundreds of faults that have been identified. The good news for us is that most of those have been inactive and don’t really have any motion to them,” Earman said.

Since Colonial times, people in the Lancaster Seismic Zone have felt small earthquakes and suffered damage from larger ones, according to the USGS website. Earthquakes are felt once or twice per decade, with some decades having none and the 1990s having as many as six, according to the USGS.

Earman said it’s hard to pinpoint exactly why this area of southeastern Pennsylvania has a seismic zone.

It’s thought that the formation of the Appalachian Mountains could have led to some of the fault lines in the area.

The area is also prone to sinkholes.

Sometimes, if there is a lot of rain in an area with sinkholes, it could trigger movement in one of the fault lines, Earman said.

Luckily, the majority of Pennsylvania earthquakes are small, Earman said.

Those that are magnitude 2.0 or less usually last less than a minute.

“People are certainly going to notice. You can hear some rumbling, or booms can be heard. Something might fall off the wall, but we wouldn’t expect to see any structural damage,” Earman said.

By comparison, a magnitude 8 earthquake could last at least several minutes and cause major structural damage, Earman said.

While the majority of earthquakes in Pennsylvania are small, there have been some significant ones.

On Jan. 16, 1994, a magnitude 4.6 was felt near Wyomissing Hills, just west of Reading. Dozens of homes received damage to foundations and walls, and it caused a sinkhole nearly eight feet deep and 25 feet wide, according to an article in the New York Times.

An even bigger quake shook the region on Aug. 23, 2011, though the epicenter of that 5.8 magnitude quake was hundreds of miles away in Mineral, Va. Tremors from that event were felt up and down the east coast, including in the Lehigh Valley.

CAPTION

Einstein the camel, who captured the Lehigh Valley’s imagination along Route 309 in last week’s freak snowstorm, has been fielding media inquiries from as far away as Florida. (Harry Fisher / The Morning Call)

Einstein the camel, who captured the Lehigh Valley’s imagination along Route 309 in last week’s freak snowstorm, has been fielding media inquiries from as far away as Florida. (Harry Fisher / The Morning Call)

CAPTION

Einstein the camel, who captured the Lehigh Valley’s imagination along Route 309 in last week’s freak snowstorm, has been fielding media inquiries from as far away as Florida. (Harry Fisher / The Morning Call)

Einstein the camel, who captured the Lehigh Valley’s imagination along Route 309 in last week’s freak snowstorm, has been fielding media inquiries from as far away as Florida. (Harry Fisher / The Morning Call)

CAPTION

From the moment a woman’s badly decomposed body was pulled from Williams Township basement, there were many questions. Who is she? How did she die? Who put her in that box?Introducing Funny Girl, a four-part series and podcast by The Morning Call.

From the moment a woman’s badly decomposed body was pulled from Williams Township basement, there were many questions. Who is she? How did she die? Who put her in that box?Introducing Funny Girl, a four-part series and podcast by The Morning Call.

CAPTION

The second annual Lehigh Valley Vegan s’ Mac Down is held at Bethlehem's Musikfest Café on Sunday, Nov. 18, 2018. (Harry Fisher / The Morning Call)

The second annual Lehigh Valley Vegan s’ Mac Down is held at Bethlehem's Musikfest Café on Sunday, Nov. 18, 2018. (Harry Fisher / The Morning Call)

CAPTION

A view from 7th Street in Allentown as Thursday’s storm brought traffic to a halt for hours.

A view from 7th Street in Allentown as Thursday’s storm brought traffic to a halt for hours.

CAPTION

Atria Senior Living in Hannover Twp., Northampton County holds a 100th birthday celebration for Evelyn Grammes

Atria Senior Living in Hannover Twp., Northampton County holds a 100th birthday celebration for Evelyn Grammes